Metal deforming – By extruding through orifice – By rotating impeller means
Reexamination Certificate
2000-08-15
2002-04-16
Tolan, Ed (Department: 3725)
Metal deforming
By extruding through orifice
By rotating impeller means
C072S253100, C072S256000, C072S270000
Reexamination Certificate
active
06370930
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a continuous shear deformation device, and more particularly, to a continuous shear deformation device suitable for making the amount of shear deformation of a material to be uniform throughout upper and lower parts of the material, increasing the amount of shear deformation, and occurring a rapid shear deformation.
2. Description of the Background Art
The shear deformation process is a process of obtaining a sheared material by passing a material into a mold for shear deformation having a molding path at which a curved portion is formed, and allowing shear deformation of the material to occur at the curved portion. This process has the object of fabricating a material of high strength and high plasticity by improving the strength of the material and forming a texture having a certain direction.
The above-mentioned shear deformation processes includes equal channel angular pressing (ECAP), equal channel angular drawing (ECAD), continuous ECAP process, and so on.
FIGS. 1
a
,
1
b
,
2
a
, and
2
b
are views schematically illustrating shear deformation devices performing these shear deformation processes, respectively. As illustrated therein, the shear deformation devices are identical with one another in that each shear deformation device is constructed of molds
1
,
2
,
6
,
7
,
12
, and
13
provided with molding paths
3
,
8
and
14
having a curved portion shown in dotted line, but they are different from one another with respect to a means for applying power in order to passing materials
5
and
9
through the molds
3
,
8
and
14
.
Among these shear deformation processes, in case of equal channel angular pressing by which the material
5
is pushed out by a punch
4
, only a sheared material of a limited length is obtained. Once the material is scalped, the next material can be provided only after extracting the punch
4
from the molds
1
and
2
, so it is impossible to continuously mass-producing sheared materials. In case of equal channel angular drawing, although it is possible to mass-produce sheared materials, it is difficult to practically use this process because it has little effect for shear deformation. For the continuous mass production of materials having an appropriate amount of shear deformation, a continuous shear deformation device illustrated in
FIGS. 2
a
and
2
b
which uses rotary guide apparatuses
10
,
11
,
15
, and
16
in place of the punch
4
in order to continuously perform equal channel angular drawing is suitable.
However, the conventional continuous shear deformation device schematically illustrated in
FIGS. 2
a
and
2
b
has the following problems.
First of all, in case of the continuous shear deformation device as illustrated in
FIG. 2
a
, the friction surface between the material
9
and rotary rolls
10
and
11
of the rotary guide apparatus is so small that it is difficult to effectively push the material
9
into the molds
6
and
7
. That is, the power for shear deformation of the material
9
in a curved portion, which is a part of the molding path
8
in the molds
6
and
7
, and the power for overcome the friction force of the contact portion between the material
9
and the molds
6
and
7
must be applied to the material. Nevertheless, in case of the device illustrated in
FIG. 2
a
, the friction surface between the material
9
and the rotary rolls
10
and
11
is so small that the above powers cannot be effectively transferred from the rotary guide apparatuses
10
and
11
toward the direction of the material.
In addition, as illustrated in
FIG. 2
b
, in case of the continuous shear deformation device constructed in such a manner that the friction surface between the material
9
and the rotary roll
15
is increased, the above powers can be effectively transferred from the rotary guide apparatuses toward the direction of the material. However, it is difficult to machine a contact portion A simultaneously contacting the rotary guide apparatuses and the material, and the buckling phenomenon of the material is occurred due to the gap between the contact portion A and the material
9
.
In addition, the conventional continuous shear deformation device illustrated in
FIGS. 2
a
and
2
b
has a problem that the material is not tightly attached to a lower mold in the curved portion in the mold, thus making the amount of shear deformation of a lower part of the material insufficient.
FIG. 3
is a view illustrating the calculation of the amount of shear deformation of a material in a curved portion in a mold by simulation. By this, it is known that a board plank is not completely attached to a molding surface at the curved portion directed by an arrow, but is isolated therefrom. Accordingly, it is known that the amount of shear deformation in the lower portions of the material is not sufficient as compared to other portions, which is confirmed by an actual experiment performed by the inventors. That is, the scales indicated in a vertical direction on the sides prior to shear deformation of the material as shown in
FIG. 4
a
are indicated as shown in
FIG. 4
b
after passing through the continuous shear deformation device, which indicates that the amount of shear deformation in the lower portions of the material is smaller than that in other portions.
In addition, in the conventional discontinuous or continuous shear deformation devices described above, a curved portion is formed at the center of molding path
3
,
8
and
14
having the same width, and thus the movement of the material is inhibited by the friction at the molding path excepting the curved portion at which shear deformation is actually occurred. Therefore, a considerable power plus the power required for shear deformation in the curved portion has to be additionally applied to the materials, which is ineffective.
In addition, there is another problem that the life span of the molds is not long because the abrasion occurred adjacent the curved portion which receives the largest friction force from the molding paths rapidly performed as compared to other portions.
SUMMARY OF THE INVENTION
Accordingly, the objects of the present invention disclosed to overcome the problems encountered in the conventional art will now be described.
It is an object of the present invention to provide a continuous shear deformation device capable of effectively transferring power in the direction of a material from a rotary guide apparatus without difficulty in fabricating a mold, and thus smoothly performing shear deformation of the material.
It is another object of the present invention to provide a continuous shear deformation device having no possibility of buckling phenomenon of the material occurred at the entrance of a molding path.
It is still another object of the present invention to provide a continuous shear deformation device capable of obtaining an uniform and sufficient amount of shear deformation throughout the material by assuring contact between a lower part of the material and a curved portion in a molding path at which the material is sheared.
It is another object of the present invention to provide a continuous shear deformation device capable of assuring a longer life span of the mold.
It is another object of the present invention to provide a continuous shear deformation device which can be compatibly used in response to materials of different thickness, that is, from thin-walled materials to thick-walled materials.
To achieve the above objects, there is provided a continuous shear deformation device in accordance with the present invention which includes: a mold having a molding path which a material passes through; and a rotary guide apparatus for guiding the material to the molding path, wherein a curved portion is constructed by collaboration between the rotary guide apparatus and the opening of the molding path, so that shear deformation may be occurred at the position at which the material is inserted into the molding path from the rotary guide apparatu
Chung Young-Hoon
Lee Ho-In
Lee Jae-Chul
Park Jong-Woo
Seok Hyun-Kwang
Korea Institute of Science and Technology
Scully Scott Murphy & Presser
Tolan Ed
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